Photosensitive counter circuit of the binary scaler type



June 22y 3965 R. M. wlLMoTTE PHOTOSENSITIVE COUNTER CIRCUIT OF THE BINARY SCALER TYPE Filed Sept. 8, 1959 United States Patent O 3,191,041 PHTSENSHTIVE @GNTER CIRQUE F THE BENARY tlCALER TYPE Raymond M. Wilmotte, Princeton, NJ. (4301 Massachusetts Ave. NW., Washington, D.C.) Filed Sept. 8, 1959, Ser. No. 835,451 19 Claims. (Cl. Z50-209) The present invention relates to electrical counter circu-its of the binary scaler type, and more particularly is concerned with such circuits wherein the basic components are couples of photoresponsive elements and variable light sources. The present invention is related to my cepending application S.N. 620,831, filed November 7, 1956, and copending application S.N. 607,770, tiled September 4, 1956, by myself and Robert L. Cam-ine, jointly.

In their preferred, and what is presently considered their most practical embodiments for the present purposes, the aforementioned couples comprise photoconductors, such as cadmium Isulfide crystals, as the photoresponsive elements, and light :transmitting electroluminescent condensers, or cells, as the variable light sources. Photoconductors in the form of suitably activated cadmium sulfide crystals are well known, and such elements can be readily formed possessing relatively wide ranges of photoresponse and time characteristics to illumination. Light transmitting electroluminescent oondensers are also Well known, and in their more usual form possess the property of emitting light in proportion to the magnitude of A.C. voltage impressed thereacross. These electrolumines'cent condensers also have the property of a threshold voltage, below which the condensers remain substantially dark or non-luminant.

In accordance with the present invention, by appropriate electrical and luminance coupling of electric signal re sponsive variable l-ight sources and pho-toresponsive elements, such as the types above referred to, circuits can be formed broadly yfunctionally equivalent to conventional counters, such as vacuum tube and magnetic counters.

The present invention being directed to counter circuits of the binary scaler type, it comprises the combination of a plurality of units or stages appropriatelyintenrelated or coupled to perform a logical function, particularly the counting Iof input signals or pulses on the binary scale. In particular, these binary stages are related and are preset by a planned -or preestablished assymetry in the several stages, so that the register of binary stages will oper-ate on a radix other than two, and in the preferred embodiment, the register is preset to operate on a radix of ten.

'Each of the units or stages includes a flip-flop or scale-of two circuit formed from two variable light sources and two photorespons-ive elements appropriately coupled to 'said light sources optically and electrically, t-o impart to the unit or stage two stable states-a 0 sta-te with a fir-st of the light sources luminant and the other non-luminant, and a l state with said first light source non-luminant and said other luminant. Each such stage is adapted to be -switched from its existing stable state to its other stable state upon the application of each input pulse thereto.

Further, appropriate photoresponsive carry circui-ts are associated with each `stage so as to couple any input pulse applied to a given stage to the next succeeding stage when the given stage is in the l state at the time said input -this process, the input pulse causes each stage through which 1t is coupled and said first 0 state stage to sw1tch to its other stable state.

3,191,041 Patented June 22, 1965 yIt is accordingly one object of the present invention to provide a novel counter circuit.

Another object of the present invention is to provide such a circuit utilizing electric signal respons-ive variable light sources coupled with photoresponsive elements as the basic components of the circuit.

Another object of the present invent-ion is to provide such a circuit utilizing electroluminescent condensers or cells and photoconductors as the basic components of the circuit.

Still another object of the present invention is to provide a circuit which is broadly functionally equivalent to conventional counters, wherein pho-toconductors and light transmitting electroluminescent coudensers are utilized as the basic components of the circuit.

An additional object of the present invention is to provide a counter ofthe binary sealer type, in which the basic elements or components of the circuit are photoresponsive elements and variable light sources electrically and optically coupled together, particularly where said photoresponsive elements are solid state photoconductors, and said light `sources are solid state electroluminescent cells or capacitors.

Anda .still further object of `the present invention is to provide such a counter which is preset to function as a Scaler wherein the register operates on a radix of other than two, and preferably ten.

f Other objects and advantages of the present invention will become apparent to those skilled in the art from a consideration of the following detailed description of an exemplary specific embodiment thereof, had in conjunction with :the accompanying drawing in which:

FlG. l is a schematic presentation of one embodiment of the invention; and

FIGS. 2 and 3 are functional block diagrams and schematic of shift register circuits in accordance with the presen-t invention.

Referring to FIG. 1, the counter there illustrated cornprises four identical binary stages 10, 2t), 30, and 40. Binary stage 10 comprises two arms in electrical parallel relationship between an A.C. bias source 61 and ground 62. One arm includes the electrical series elements of resistor 17 and electroluminescent cell or capacitor 11, and the other arm includes the electrical series elements of resistor 18 and electroluminescent cell or capacitor 12. In addition photoconductor 14 is connected in electrical parallel relationship with cell 11 with respect to the bias source 61, and is optically coupled to cell 12. Correspondingly, photoconductor 13 is connected in electrical parallel relationship with cell 12 with respect to the bias .source 61, and is optically coupled to cell 11. The net work thus far described for stage 1i) constitutes a flipflop circuit, as will become apparent from the subsequent description of its operation. In order to introduce a prescribed or planned asymmetry into this flip-flop circuit, a resistor 15 is connected across cell 12.

Thus, with regard to stage 1l), when the bias Voltage 61 is initially applied to the circuit, as by closing switch `631 (photoconductor 68 being assumed to be in alow impedance state), stage 1li assumes the stable state of cell 11 luminant and cell 12 extinguished. This result is accomplished by choosing the parameters of the circuit so that when switch 63 is initially closed, the voltagesV across cells 11 and 12 from the bias source 61 are both in excess of their threshold values. However, because of the unbalance caused by resistor 15, the voltage across cell 11 is greater than that across cell 12, hencecell 11 luminesces more brilliantly than cell 12.A As these cells 11 and 12 luminesce, their respective optical couplings with photoconductors 13 and 14 cause the resistances of these photoconductors to decrease. Since cell 11 is luminescing more brilliantly than cell 12, photoconductor photoconductor 14. As a result, the decrease in resist- 1 ance of photoconductor 13 causes the VoltageV applied across cell 12 to drop below its threshold value, and cell 12 becomes non-luminant. The optical coupling between cell 12 and photoconductor 14 initially has a similar effect on -cell 111, but since cell 1&1 starts from a more brilliant or higher voltage condition than cell 12,' cell 11 does not become extinguished and the stage soon reaches the stable state of cell 11 lumin'ant and cell 12 non-luminant Yor extinguished. With cell 12 extinguished, photoconductor 14 soon attains its full impedance'value, and cell 11 attains its full luminance under the bias voltage. This stable state of the binary stage 10 is identied as the 0 state.

Each of the stages 20, 30, and 40 are identical to stage 10, both in structure and response to the bias voltage, except that in stages 2t) and 30 the unbalancing resistors and 35 are placed across cells 21 and 31 instead of cells 22 and 32. From the foregoing description it is apparent that these stages therefore respond to the initial application of the bias voltage by each attaining the l state, i.e., cells 22 and 32 luminant, and cells 21 and 31 non-luminant. Therefore the structure and response of these stages need not be further specioallydescribed. Thus, by the initial application of the bias voltage from source 61, stage 1,0 assumes the O state, stage 20 the 1 state, stage 30 the l State, and stage 40 the 0 state. By this planned asymmetry of `the four stages, the counter is automatically preset with the binary count ofA 0110, or six. Since the full count of a four stage counter is sixteen, the present counter is therefore preset V60 is applied to stage 10 across resistor 16. Considering stage 10V to be in the stable state 0 above-defined, cell 11 is luminant and illuminating photoconductor 13, While cell 12 is non-luminant and hence photoconductor 14 is not illuminated. Photoconductor 13 is therefore a relatively low impedance and photoconductor 14 is a relatively high impedance. VSince the input pulse is coupled to each of said cells through its respective photoconduc- -tor in electrical series with -it 'with respect to the input source (series circuit 60, 13, 12., to `ground,rand series circuit 60, 14, 11, to ground), ak much greater voltage from the input pulse is passed by photoconductor 13 and applied across cell 12 than is passed by photoconductor 14 and applied across cell 11. The input pulse should V'be of sufcient value to render cell 12 substantially more luminant than cell 11. The duration of this input pulse is timed in accordance with the time characteristics of `the photoconductors, to terminate at -a time that renders photoconductor 14 more conductive than photoconductor 13 as a result'of the input pulse. This residual unbalance in the flip-flop circuit overrides the unbalance due to resistor 15, and results in a dominant luminance of cell as above-described, cell 12 was originally non-luminant. Accordingly photoconductor 19 was a relatively high resistance, and the input pulse was not passed to stage 20 with sufticientamplitude to affect this stage. However, when stage 10 is in the l state, the luminance of cell 12 illuminates photoconductor 19, and thus reduces its impedance so that the next pulse in at 60 does affect the stage 20 binary flip-flop.v Considering stage 10 to be in the stable `state 1, the next pulse in at 60 is applied to stage 10 across resistor 16, and being passed by photoconductor 19, is simultaneously applied to stage 20 across resistor 26. Since stages 20 and 30 are also in the "1 state at the time of application'of this second input pulse, this pulse is passed by photoconductor 29 to the input resistor 36 of stage 30, and similarly, passed' by photoconductor 39 to the input resistor 46 of stage 40. Since stage 40 was in the 0 state at the time of application of this second pulse, photoconductor 49 is a high impedance, andthe input pulse is not passed beyond stage 40. Having been applied t0 stages 10, 20, 30, and 40, this second input pulse causes all these stages to switch from their existing state to their other stable state, stages 12 over cell 11, and the establishment of Vstable state 1 in stage 10, with cell 12 fully luminant from the bias source 61 and cell 11 extinguished, it being shunted by the low impedance of the illuminated photoconductor 14. Similarly, if stage 10 .is in the l state with cell `12 luminant, from the foregoing it is apparent that upon the ,application of an input pulse at 60 the stage is caused 10, 20 and 30 are each switched from 1 state to' 0 state, and stage 40, from 0 state to l state. The third input pulse at 60 is applied to stage 10 across stage input resistor 16, causing this stage to switch from "0 state to l state, but is not passed by photoconductor 19 to stage 20. The fourth input pulse at 60 is applied to stage input resistor 16, causing stage 10 to switch from "1 state to 0 state, and is passedby photoconductor 19 to the stage input of stage 20, causing stage 20 .to switch from the 0 state to the 1 state. Photoconductor 29 blocks this fourth pulse from any further effect on the circuit. The further response of this circuit to succeeding input pulses at 60 can be readily ascertained from the foregoing description.

As a result of the ninth input pulse at 60, the counter attains the condition of all stages in the "1 state. There- -fore thetenth input pulse applied to input 60 causes stage 10 to switch to the 0 state, is coupled by photoconductor 19 to the stage 20 input where it causes stage 20 to switch to the "0 state, is coupled by photoconductor 29 to the stage 30 input where it causes stage 30 to switch to the 0 state, is coupled by photoconductor 39 to the stage 40 input where it causes stage 40 to switch to the 0 state, and is coupled by photoconductor 49 to the counter output 72. Output 72 may be coupled to the input of a second register, so that the full count of ten attained by the present register may be applied as a unit count in aregister of the next higher order.

From the foregoing discussion, the counter would be left with all stages inthe 0 state. If this were the case, thefsecond operational cycle of the counter would not operate as a decade scaler in the manner aforedescribed. To continue to operate as a decade sealer, means must be provided to automatically reset the counter to the binary count of 0110, or six. This is effected in the present embodiment by coupling the tenth pulse appearing in the output 72 to electroluminesc'ent condenser or cell 70, luminance coupled to photoconductors 73 and 74. Thus, the output pulse at 72 causes cell 70 to luminesce, resulting in photoconductors 73 and 74 attaining a low impedance. This effect causes an increase in the voltage from source 75 (which could bel the same as bias source 61) applied across cells 22 and 32 of suicient magnitude to cause these cells to luminesce substantially more brilliantly than cells 21 and 31. Photoconductors 24 and 34 are thus rendered more conductive than photoconductors 23 and 33. Accordingly, when the pulse on cell 70 terminates, stages 20 and 30 are caused to obtain the "1 state provided in the planned asymmetry by resistors 25 and 35. The counter is thus reset at a preset count of six (0110), its zero condition, in readiness to count the next ten input pulses for a full counter count of sixteen.

Other circuits thanithat specically described may be employed to reset the counter to a desired preset value. For example, instead of applying a voltage pulse to cells 22 and 32 through photoconductors 73 and 74, these photoconductors could be employed to shunt cells 21 and 31, with the same result of causing stages 20 and 30 to obtain a "1 state. Of course, the same circuits and principles for the planned preset asymmetry and automatic reset can be employed for presets other than 0110, to btain registers having any desired radix.

In the foregoing description of the present invention, it was pointed out that an input pulse at 60 is coupled from one stage to the next by the carry photoconductor only when said one stage had been in a l state at the time the input pulse was applied. However, when an input pulse is applied to a 0 state stage, it is switched to a l state during the existence of the input pulse. Therefore, the timeduration of the input pulses and the response times of the carry circuit photoconductors are chosen so that a given input pulse is terminated before the carry photoconductor of such a switched stage has reached sufcient conductivity to effectively couple the pulse into the next stage.

In addition to the automatic reset above-described, the present counter may at any time be reset to its preset starting value or condition by interrupting the bias supply for a suihcient time to permit all the elements of the circuit to attain their deenergized state, and then reapplying the bias voltage. The circuit will assume the condition prescribed by the planned asymmetry of the several stages, which in the instant illustration is the pre- Vset condition of stages 10 and 40 in "0 state, and stages 20 and 30 in "1 state. Assuming photoconductor 63 to be illuminated and in a low impedance state, the foregoing interruption of the bias supply can be accomplished by means of switch 63. Resetting by means of switch 63 can of course be effected without the presence of photoconductor 68 in the circuit.

Photoconductor 68 in series with the bias source 61 can also function as a switch to eifect resetting of the counter in responsey to an electrical reset pulse applied at reset input 64. Normally, no reset pulse is applied at 64, so cell 65 is non-luminant, photoconductor 66 optically coupled thereto is not illuminated and hence ;is a high resistance, whereby the voltage at 69 is"sufiicient to render cell 67 luminant. The luminance of cell 67 is applied to photoconductor 68 to render this element a relatively low impedance and result in application of a normal bias voltage to the counter. However, upon the application of a reset pulse to reset input 64, cell 65 luminesces, illuminating photoconductor 66, so Vthat its resultant low resistance shunts and thereby extinguishes cell 67. With the extinguishment of cell 67, photoconductor 68 becomes a high resistance, thereby eectively cutting off the bias voltage to the counter, and causing all the elements thereof to revert to their non-energized state. Upon termination of the reset pulse, cell 65 becomes extinguished, causing photoconductor 66 to regain its non-illuminated high impedance, as a result of which cell 67 again luminesces under the excitation of the bias voltage causing photoconductor 68 to become a low impedance. Thus the bias potential is again effectively applied to the counter, and the counter assumes its zero condition as required by its planned asymmetry.

n As thus far described, 'the counter cyclically indicates by the condition of its binary stages the binary notations `from 0110 to 1111, equivalent to the decimal numbers lsix to 15. The true values of these notations are, however, in terms of actual numbers of pulses applied to the counter input 60, zero to 9. The present invention therefore provides for an optical output which presents the actual number of pulses applied to counter input 60 in binary notation running from 0000 to 1001, equivalent to the decimal numbers zero to nine. This effect is accomplished in the present embodiment by providing the v additional elements of electroluminescent cell 80, electroluminescent cell 90, and photoconductor 91. Cell is connected between photoconductors 24 and 34 at 81 and V82, and will luminesce only when these two photoconductors are in opposite state, i.e., one relatively conductive and the other of a relatively high impedance. Since the corresponding elements in the several stages are substantially equal in value, it is apparent that there will be a significant voltage drop across cell 80 only when the photoconductors 24 and 34 are in diiferent resistive states. Cell is connected between photoconductors 33 and 44 at points 92 and 93, and like cell 80, this cell can luminesce only when the latter photoconductors are in diiferent states to provide a signiiicant voltage drop across cell 90. In addition photoconductor 91 is connected in electrical series with cell 90, and is optically coupled with cell 22. Thus, for cell 90 to luminesce, not only must the photoconductors 33 and 44 be in diiferent resistive states, but cell 22 must be luminant to place photoconductor 91 in a low resistance state. One may now consider the optical output of the counter from cells 12, 21, 80, and 90, a luminescing cell being considered the l state and an extinguished cell,'the 0 state. The following table gives a comparison of the response of stages 10, 20, 30, and 40 with cells 12, 21, 31), and 90 for each pulse in the decade cycle:

Stages Cells Pulse 0 1 1 0 0 0 0 0 1 1 1 0 1 0 0 0 0 0 0 1 0 1 0 0 1 0 0 1 1 1 0 0 0 1 0 1 0 0 1 0 1 1 0 1 1 0 1 0 O 0 1 l 0 1 1 0 1 0 l l 1 1 1 0 0 1 1 1 0 O 0 1 1 1 1 1 1 0 0 1 Thus cells 12, 21, 80, and 90 provide an optical output or read-out for the counter inv conventional binary notations corresponding to a count of one to ten input pulses.

To better illustrate the shift register aspect of the present invention, it is illustrated in combined block diagram and schematic fashion in FIGS. 2 and 3. VThe shift register function constitutes the application of a pulse indicative of a complete count in one register as a unit input in the register of next higher order, together with resetting the said one register. In FIGS. 2 and 3, two exemplary registers are indicated, register A by numeral 101 and register B by numeral 102. These' registers, like that of FIG. 1, are designed to issue a pulse upon reaching a full count for which the register is designed, and register B is intended to represent the next .higher order after register A. Thus, when register A photoconductor 104, causing the pulse P to be coupled back into the register A to effect a desired reset of this register. If the magnitude of pulse P alone is not sucient to eiect the desired reset operations in the register A, it may, of course, be supplemented by a bias voltage source, not specifically shown.

Instead of feeding back fthe output 'pulse P, the reset of register A may be effected .by .a separate source of voltage as shown in FIG. 3. Here the pulse P, resulting `from a full count in register A is applied to register B as -a unit input, in the same manner as in FIG. 2. However, in the lreset circuit, lpulse P -is applied yon'ly across electro-luminescent cell `103. The luminance cou- 'pliug between cell :w3 yand prliotoconductor 104 causes v'the latter to be reduced in impedance and thus cause a sufficient reset voltage from sour-ce tlSto be applied to register A in a manner appropriate to reset this register to its desired initial or zero state. In view of the -speciiic `description of the register of -F-IG. 1 and its reset operation, it is yapparent that instead applying an increase in voltage to the reset circuit through source 1&5,

this voltage source may be eliminated,` and the reset pulse can be in terms of 'ai decrease in volt-age in `the reset circuit, as vetected mer-ely by a decrease in iinpedance .of pliotoconductorY 1943.

Accordingly, by the present invention there is provided a binary readout decade counter, comprised ot variablel 'light ysource-photoresponsive element couples, wherein the counter is of the binary sealer type, having a plurality of binary l'lip-tlop stages, with appropriate carry or V coupling circuits interrelatirig .the several stages. Having presented one specific exemplary embodiment of the invention, it is understood that the scope ofthe invention is not limited thereto, for changes, inodications, and variations will tbe appar-ent to those skilled in the art.

Forfexample, it will abe apparent that the present decade i counter can be readily converted in accor-dance with the principles of the .present invention to a trinary counter, quaternary counter, or to any otlier radix desired, by lappropriate preset asymmetry of the binary stagesaiid automatic reset circuitry.

What is claimed is:

'1. A .binary sealer tor cyclically counting a prescribed Y num-berof input signals less than the full count of which the sealer is 4capable and resetting to a prescribed starting condition, comprising: a plurality of stages; each stage including a bi-stableV circuit cyclicallyV operable between .a trst and a second stable state, andan input r mean-s for each saidcircuit; `and a carrymearis in corribination with leach two successive stages interrelating sa-id two stages; each said circuit comprising voltage responsive variable light means and photoresponsive means :mea-ns; said first and .second stable states being defined rby different states of said light means; each said carry means including means optically coupled with said light. (means of the earlier of its respective two stages for coupling an input signal to the input means of tbe later of itsrespective two stages along with the application or" an input signal ft-o the input means of said earlier stage, only when said earlier stage is .insaid second stable sta-te at the time of application of the last-mentioned input signal; and reset means including actuator means coupled to said stages and responsive to the condition of the scaler upon receiving .su-ch prescribed numberrof input signals for resetting the sealer to said prescribed startying condition, said reset means comprising a voltage responsive variable light means cont-rolled by the condin tion of the sealer tto become luminant wchenfthc sca-ler 'has received said prescribe-d number of input signals, and

photoresponsive means 'optically' coupled to the laSt`-.

Adition.

2. A binary scaler `as set forth inclaim l, wherein said optically coup-led means of each carry means comprises ya photoresponsive element.

3. A binary sealer as set forth in claim 2: further including an input :means lfor the scaler'associated with Vthe -fiist stage; yand wherein all theycarry means are conf lnected in :electrical series with respect to said input me-ans for the sealer, whereby a signal input to said input means for the Scaler is y.applied 'to successive cir-cuit input means lin accordance with the response of said carry vmea-ns.

4. A binary scaler for cyclically counting a prescribed number of input signals less than the full coun-t of which the scalerris capable and resetting to a prescribed sta-rting condition, comprising; a plurality of stages; each Vstage including a bi-stab-levcircuit -cyclically operable be- .tween .a irst yand a second stable state, and an input mean-s ytor each said circuit; and acarry means in combination with each two successive stages interrelating said two stages; Iea-ch said circuit comprising Itwo voltage responsive vari-able light `sources and 4at least one photo- Yresr'iorisive ele-ment electrically coupled to one lightsource and optically coupled to the other light source; sai-d light sources and photoresponsive element of each said circuit cooperating in response to successive :input signals applied tothe respective input means to eifect said cyclical operation, one .cycle of operation for each pair of `input signals -applied to sai-d respective input means; said iirst Yand second stable states bei-ng defined by "ditherent states tot said light sources; cach said carry means including mie-ans optically coupled with one of -said light sources of the earlier ol" itsl respective two stages for coupling an linputY signal to the input means of the later of its :respective two stages along with the appli-cation of an input signal to the input means of said earlier stage, only 'when .said earlier stage is in said second stable `ist-ate at the time of application of the last-mentioned input signal; and reset means including lactuator means coupled to said stages land responsive to the condition of the s-caler upon receiving said prescribed number of input ,signals for 4resetting the sealer to said prescribed starting condition, Vsaid reset means comprising a volt-age responsive variable light means cont-rolled by the .condition of the scaler to become luminant when the sealer yhas received said prescribed number or" input sign-als, and photoresponsive means optically coupled tothe last-mentioned light means `and electrically coupled to at least one stage lof the. Scaler for biasing such stage into that stable state denoted by said prescribed starting condition. y5. A binary scale-r as set forth in claim 4, wherein said optically coupled means of each carry means comprises Va photoresponsive element. 6. A binaryrscaler as set forth in claim `5; further including an input means for the seal-er associated with the v.tir-st stage; and wherein all the carry means are connected in electrica-l series with respect to said input means vfor the Scaler, whereby -a signal input to said input means for the .Scaler is applied to successive cir-cuit input means in accordance with the response of said carry means.

, 7.. A binary sealer for cyclically count-ing a prescribed number of input signals less than the full count of which the sealer is capable -and'resetting to a prescribed starting condition, comprising: a plurality of stages; each stage including a bi-stable circuit cyclically operable between a yfirst and `a second stable state, and an input means for each said circuit; and a carry means in com- ."bination with each two successive stages inter-relating said two stages; each said circuit comprising two voltage responsive variable light sources and two photoresponsive elerricnts, one of said elements Abeing connected electrically across one of said sources and being optically coupled to the other of said sources, the other of said elementsvbeing connected electrically to said other of said sources and being optically coupled to said one of said sources, said `light sources and photoresponsive elelments of each said ycircuit cooperating inresponse to successive input signals .appliedto the respective input 'means to effect said cyclical operationyone cycle of opof its respective two stages along with the application of an input signal to the input means of said earlier stage, only when said earlier stage is in said second stable state at the time of application of the last-mentioned input signal; and reset means responsive to the condition of the sealer upon receiving said prescribed number of input signals for resetting the sealer to said prescribed starting condition, said reset means comprising a voltage responsive variable light means controlled by the condition :of the sealer to become luminant when the sealer has receive-d said prescribed number of input signals, and photoresponsive means optically coupled to the last-menti-oned light means and electrically 'coupled to at least one stage of the sealer for biasing such stage into that stable state .denoted =by said prescribed starting condition. v

8; A binary sealer as set forth in claim 7: further including .an input means for the Scaler associated with the trst stage; .and wherein all the carry means :are connected in electrical series with respect to said inputmeans for .the sealer, whereby input to said input means -for said sealer is applied to successive circuit input means in accordance with the response of said carry means.

)9. A 'binary' sealer for cyclically counting a prescribed number of input signals less than .the full count of which the sealer is capable and resetting to a prescribed start'- ing condition, comprising: a plurality of stages; each stage including a bi-stable circuit cyclically operable between -a first and a second stable state, Iand `an input means for each said circuit; and a car-ry means in combination with each two suceesive stages interrelating said vments being connected electrically across said other of said sources and 4being optically coupled to said one 0f said sources; 'said input means comprising means for applying a-n input signal simultaneously across said one element .and said one-.source in electrical series with respect thereto, and lacross said other element and said other source in electrical series with respect thereto; said light sources and photoresponsive elements of each said cireuitcooperating inpresponse to successive input signals applied .to the respective input means to effect said cyclical operation, one cycle of operation for eaeh pair 'of input signals applied to said respective input means; said tirstrand second stable states being defined by diiterent states'l of said light sources; each said carry means including a photoresponsiv-e element optically coupled with said other of said light sou-rees of the earlier of its respective two stages for coupling an input signal to the input means of the later of its respective two stages along'with the yapplication `ot .an input signal t-o the input means of said earlier stage, only when said earl-ier stage is in said second stable state at .the time ot application of the last-mentioned input signal; and reset means responsive to the condition of the sealer upon receiving said prescribed number of input signals for resetting the sealer to said prescribed starting condi-tion, sai-d reset means comprising ya voltage responsive variable iight means controlled 'by the icondition of .the sealer to become luminant when'the sealer has received said prescribed number of input signals, and photoresponsive means optically coupled to the last-mentioned light means and electrically coupled to at least one stage ofthe sealer for biasing such stage int-o that stable state denoted by said prescribed starting condition.

10. A binary sealer for optically counting a prescribed number of input signals less than the full count of which the sealer is capable and resetting to a prescribed starting condition, comprising: a plurality of stages; an input means for the sealer associated with the first stage; each stage including a bistable circuit cyclically operable between a tirst and a second stable state, and an input means for each said circuit; and a carry means in combination witheach two successive stages interrelating said two stages; each said circuit comprising two voltage responsive variable light' sources and two photoresponsive elements, one of said elements being connected electrically across one of said sources and being optically coupled to the other of said sources, the other of said elements being connected electrically to Said other of said sources and being optically coupled to said one of said sources; said circuit input means comprising means for applying an input signal simultaneously across said one element and said one source in electrical series with respect thereto, and across said other element and said other source in electrical series with respect thereto; said light sources and photoresponsive elements of each said circuit cooperating in response to successive input signals applied to the respective circuit input means to effect said cyclical operation, one cycle of operation foreach pair of input signals applied to said respective circuit input means; said first and second stable states being defined by different states of said light sources; each said carry means including a photoresponsive element optically coupled with said other of said light sources of the earlier of its respective two stages for providing an input signalto the circuit input means of the later of its respective two stages in response to an input signal applied to the circuit input means of said earlier stage, only when said earlier stage is in said second stable state at the time of application of the last-mentioned input signal; all the carry means being connected in electrical series with respect to said signa1 input means for the sealer, whereby a signal input to said input means for the sealerv is applied to successive circuit input means in accordance with the response of said carry means; and reset means responsive to the condition of the sealer upon receiving said prescribed number of input signals for resetting the sealer to said prescribed starting condition, said reset means comprising a voltage responsive variable light means controlled by the condition of the sealer to become luminant when the sealer has received said prescribed number of input signals, and photoresponsive means optically coupled to the last-mentioned light means and electrically coupled to atleast one stage of the scaler'for biasing such stage into that stable state denoted by said prescribed starting condition. v

11. A binary sealer for cyclically counting a prescribed number of input signals less than `the -full count of which the sealer is capable Yand resetting to a prescribed starting conditiomcomprising: a plurality of stages; an input means for the sealer associated with the first stage; each stage including a bi-stable circuit cyclically operable between a lirst and a second stablestate in response to input signals thereto, and an input means for each said circuit;

and a carry means in combination with each two successive stages interrelating said two stages; each said circuit comprising a voltage responsive variable light means, and said first and second stable states being defined by different states of said light means; each said carryvmeans including a photoresponsive element optically coupled with said light means of the earlier of its respective two stages for providing an input signal to the circuit input means of the later of its respective two stages in response to an input signal applied to the circuit input means of said earlier stage, only when said earlier stage is in said second stable state at the time of application of the last-mentioned in put signal; all the carry means being connected in elecn trical series with respect to said signal input means for the sealer, whereby a signal input to said input means for the sealer is applied to successive circuit input means in accordance with the response of said carry means; and reset means responsive to the condition of the sealer upon receiving said prescribed number of input signals for resetting the sealer to said prescribed starting condition, said reset means comprising a voltage responsive variable light means controlled by the condition of the sealer to be come luminant when the scaler has received said prescribed number of input signals, and photoresponsive means optically coupled to the last-mentioned light means and electrically coupledto at least one stage of the sealer for biasing such stage into that stable state denoted by said prescribed starting condition.

12. A binaryr sealer for cyclically counting a prescribed number of input'signals less than the full count'of which the sealer is Vcapable and resetting to a prescribed starting condition, comprising: a plurality of stages; each stage including a bi-stable circuit cyclically operable between a first and a second stable state, and an inpulmeansfor each said circuit; and a carry means in combination with each two successive stages'interrelating said two stages; each said circuit comprising voltage responsivevariable light means and photoresponsive means electrically and optically coupled to said light means; said circuits including means for setting selected ones of said stages in said first stable state and the others. of said stages in said second stable state, as the starting condition of the sealer, upon initial energization of the sealer; said lightmeans and photoresponsive means ofreach said circuit cooperating in 'said circuit comprising voltage responsive variable light response to successive input signals applied to the respec- ,tive input meansto effect said cyclical operation, one cycle ,of operation for each pair of input signals applied said respectiveinput means; said first and second .stable states being defined by dilerent states lof said iight means; each said carry means including means optically coupled with said light means of the earlier of its respective two stages for providing an input signal to the input means of the later of its respective two stages in response to an input signal applied to the input means of said earlier stage, only when said earlier stage is. in said second stable state at the time of application of the last-mentioned input signal; and reset means responsive to the condition of the sealer upon receiving said prescribed lnumber of input signals for feeding a signal to selected ones of said circuits for resetting the sealer to said starting condition, said Vreset means comprising avoltage responsive Variable light means controlled by the condition of the sealer to become luminant when the sealer has received said prescribed number of inputl signals, and photoresponsive means optically coupled to the last-mentioned light means and electrically coupled to said selected ones of said circuits for biasing such circuits into that stable Vstate denoted by said prescribed starting condition.

' 13. A binary sealer as set forth in claim 12, wherein said optically coupled means kof each carry means comprises a photoresponsive element.

14. A binary sealer as se't'forth in claim 13:- furtherincluding an input means for Vthe sealer ,associated with the iirst stage; and wherein all the .carry means are connected in electrical series with respect to said input means for the sealer, whereby a signal input to said input means for the sealer is applied to successive circuit input means in accordance with the response of said carry means.

15.` A binary sealer for cyclically counting a prescribed number of input signals less than the fullcount of which the sealer is capable and resetting to a prescribed starting condition, comprising: a plurality of stages; each stage including a bi-stable circuit cyclically operable between a iirst and a second stable state, and an input means for each said circuit; and a carry means associated with each two successive ystages interrelating said two stages; each means and photoresponsive means electrically and optically coupled to said light means; said circuits including means for setting selected ones of said stages in said first stable state and the others of said stages in said second stable'state, as the starting condition of the sealer, 'upon initial energization of the Scaler; said light means and photoresponsive -means `of each said circuit coopera-ting in response to successive input signalsl applied to therespective input means to effect said cyclical operation, one cycle of operation for each pair of input signals applied Said respective input means; said rst and second stable states being defined by diiierent states of said light means; each said carry means including means optically coupled with saidrlight means of the earlier of its respective two stages for providing an input signal to the input means of the later of its respective two stages in responserto an input signal applied to the input means of said earlier stage, only when said earlier stage is in said second stable state atthe time of application of the last-mentioned input signal; and reset means responsive to the condition of the Scaler upon receiving `said prescribed number of inputsignals4 fory feeding a signal to selected ones'of saidcircuits for resetting the sealer tosaid starting condition; and additional voltage responsive variable light means electrically connected between selected ones of said stages and being luminance controlled by the relation of the states ,of saidv selected stages for providing in conjunctionl with selected ones of said circuit light means a notation of the actual count of input signals in binary notation.

16. In combination, a first register of one order for counting, input signals thereto, a second register of the 4next higher order for counting input signals thereto, means kfor coupling a signal from said rst register as an input to said second register upon the iirst register reaching a .prescribedcoun and reset means responsive to said last k Amentioned signal, said reset means comprising a voltage 'responsive variable light source and a photoresponsive ele- ,ment optically coupled therewith, said light sourcel being electrically connected to said coupling means and becoming luminant in response to said last-mentioned signal, and said element beingelectrically coupled with selected Velements in said first register for resetting said first register to a prescribed condition when illuminated by said light source.

' 17. In a combination as set forth in claim 16, said element andsource being in separate electrical circuits.

18. In a combination as setforth in claim 16, said element and source being in the same circuit. l

19. In a combination as set forth in claim 16, a voltage source in electrical series with said element.

References Cited kby the Examiner UNITED STATES PATENTS nALPH G. NiLsoN, Primary Examiner. RICHARD M. wooD, Examiner. 

1. A BINARY SCALER FOR CYCLICALLY COUNTING A PRESCRIBED NUMBER OF INPUT SIGNALS LESS THAN THE FULL COUNT OF WHICH THE SCALER IS CAPABLE AND RESETTING TO A PRESCRIBED STARTING CONDITION, COMPRISING: A PLURALITY OF STAGES; EACH STAGE INCLUDING A BI-STABLE CIRCUIT CYCLICALLY OPERABLE BETWEEN A FIRST AND A SECOND STABLE STATE, AND AN INPUT MEANS FOR EACH SAID CIRCUIT; AND A CARRY MEANS IN COMBINATION WITH EACH TWO SUCCESSIVE STAGES INTERRELATING SAID TWO STAGES; EACH SAID CIRCUIT COMPRISING VOLTAGE RESPONSIVE VARIABLE LIGHT MEANS AND PHOTORESPONSIVE MEANS ELECTRICALLY AND OPTICALLY COUPLED TO SAID LIGHT MEANS; SAID LIGHT MEANS AND PHOTORESPONSIVE MEANS OF EACH SAID CIRCUIT COOPERATING IN RESPONSE TO SUCCESSIVE INPUT SIGNALS APPLIED TO THE RESPONSE TO SUCCESSIVE INPUT SAID CYCLICAL OPERATION, ONE CYCLE OF OPERATION FOR EACH PAIR OF INPUT SIGNALS APPLIED TO SAID RESPECTIVE INPUT MEANS; SAID FIRST AND SECOND STABLE STATES BEING DEFINED BY DIFFERENT STATES OF SAID LIGHT MEANS; EACH SAID CARRY MEANS INCLUDING MEANS OPTICALLY COUPLED WITH SAID LIGHT MEANS OF THE EARLIER OF ITS RESPECTIVE TWO STAGES FOR COUPLING AN INPUT SIGNAL TO THE INPUT MEANS OF THE LATER OF ITS RESPECTIVE TWO STAGES ALONG WITH THE APPLICATION OF AN INPUT SIGNAL TO THE INPUT MEANS OF SAID EARLIER STAGE, ONLY WHEN SAID EARLIER STAGE IS IN SAID SECOND STABLE STABLE AT THE TIME OF APPLICATION OF THE LAST-MENTIONED INPUT SIGNAL; AND RESET MEANS INCLUDING ACTUATOR MEANS COUPLED TO SAID STAGES AND RESPONSIVE TO THE CONDITION OF THE SCALER UPON RECEIVING SUCH PRESCRIBED NUMBER OF INPUT SIGNALS FOR RESETTING THE SCALER TO SAID PRESCRIBED STARTING CONDITION, SAID RESET MEANS COMPRISING A VOLTAGE RESPONSIVE VARIABLE LIGHT MEANS CONTROLLED BY THE CONDITION OF THE SCALER TO BECOME LUMINANT WHEN THE SCALER HAS RECEIVED SAID PRESCRIBED NUMBER OF INPUT SIGNALS, AND PHOTORESPONSIVE MEANS OPTICALLY COUPLED TO THE LASTMENTIONED LIGHT MEANS AND ELECTRICALLY COUPLED TO AT LEAST ONE STAGE OF THE SCALER FOR BIASING SUCH STAGE INTO THAT STABLE DENOTED BY SAID PRESCRIBED STARTING CONDITION. 